Air course drill bits



C. M. PIKE ETAL Nov. 26, 1957 2,814,464 I AIR couRs E DRILL BITS 3Sheets-Sheet 3 Filed Jan. 2. .1953

AIR COURSE DRILL BITS Carl M. Pike, Rockwall, and Constantine M. Xeros,Dallas, Tex., assignors to Engineering Laboratories, Inc., Garland,Tex., a corporation of Delaware Application January 2, 1953, Serial No.329,404

11 Claims. (Cl. 255-303) This invention relates to drill bits and moreparticularly to a rock bit which is used with an air supply to wash outthe cuttings and cool the bearings therein.

The primary object of this invention is to devise a structure to directair from the central shank opening to the bearings of a cone type rockbit.

A further object is to provide a structure which will be suitable foruse with a full opening bit and a similar embodiment made from the samematerial which will be suitable for a jet type bit.

A still further object of this invention is to provide an air directingmember which is economical to manu: facture and which may be used withdrill bits wherein there would otherwise be a discontinuity between theair passage in the shank and that in the spindle.

These and other objects will be apparent from the followingspecification and drawing in which:

Fig. 1 represents a cross sectional elevational view of a jet type aircourse drill bit employing this invention.

Fig. 2 represents a cross sectional elevational view of a full openingair course drill bit employing another embodiment of this invention.

Fig. 3 represents a top view of the drill "bit shown in Figs. 2 and 7.

Fig. 4 represents a bottom view of the shank only of the bit in Fig. 1.

Figs. 5 and 6 represent other embodiments of this invention and methodfor assembling same.

Fig. 7 is a modified structure of the embodiment shown in Fig. 2.

Fig. 8 is a view showing an inner face of one of the spindles of thebit.

Referring now more particularly to the characters of reference on thedrawing, in Fig. l, the drill bit of this invention is seen to consistbasically of a threaded shank 2 including a central chamber 3 with jetopenings 4, separate piece spindles 5 inserted between tines 61 attachedto shank 2 by welding 6 which forms tines 61 and spindle 5 into a singleintegral part, :and a cutter cone 7 journalled to each of the spindles5. The attaching portion of spindle 5, identified on the drawing as 105fits between tines 61 so that weld metal 6 fuses the shank 2 and spindle5 solid at their junction. The inserts 21, 41, etc. being in place atthe time of welding are not thereafter readily removable. The majorityof the drill bits in use employ three spindles and three cutter cones,but this quantity is not essential to the invention. This general typebit may be used with a water or air course.

When the bit is to be employed in an air course, that is when eithercompressed air or air at high velocity is sent down the drill stem toflush the cuttings from the hole, it is desirable to take advantages ofthe cooling effect of the air to cool the bearings. To do this, in Fig.1 an angularly disposed channel 10 is drilled through stem 2 in linewith a channel 11 in spindle 5, and an .angularly disposed channel 12connects air channel 11 with a race 13 of spindle 5. Cutter cone 7 fitsover spindle 5 and includes an alinged race 14, whereby race 13 and raceI Patented Nov. 26, 1957 14'cooperate to form a continuous raceway 15 inwhich balls 17 may move freely. Between the outer surface of spindle 5and the matching surface of cone 7 there lies a continuous passage. 18which represents the clearance between these two members. In order toform a connuous. passage of air, represented by arrow 20 enteringchannel 10, through the bearing cooling circuit, an insert 21 is placedin the gap between spindle 5 and shank 2. Insert 21 includes circularends 22 and 23 of a slightly smaller diameter than channels 10 and 11,and these ends are inserted in their respective channels prior to theapplication of weld 6. In order to retain insert 21 in its desiredposition since it is not precision machined (to reduce cost) an enlargedsection 24 is included on insert 21 intermediate the ends-22 and 23 andincluding shoulders 25 and 26 which are adapted to abut either the fiatportion 27 of shank 2 or the flat undercut 28, of spindle 5 A gap 30between one shoulder and one matching flat surface will usually be leftdue to the tolerances required in this type structure. Insert 21 in thisembodiment is made of steel or other rigid material. This insert,however, may be of anothermaterial when used in av slightly differentfashion as shown in Fig. 5, in this instance the insert 32 is a pliablematerial such as copper tube and the spindle air channel 33 is of asmaller diameter than the entrance counterbore 34 which is a smallerdiameter than tube 32 whereby the tube must be crimped as at 35 to gointo counterbore 34 until it strikes shoulder 36 at the juncture ofcounterbore 34 and channel 33. Shoulder 36 locates the insert 32 atassembly. and crimp 35 prevents it from becoming dislodged.

As previously stated the drill bit in Fig. 1 includes jet holes 4; andthis bit is used with pressurized air such as air at 40 p. s. i. inchamber 3. Since air in chamber 3 is under pressure it will enterchannel 10 from chamber 3. As indicated by arrows 20, the air enterschannel 10 and-passes through insert 21 (or 32) and through channels 11and 12 to raceway 15. In raceway 15, the pressure of the air and therotation of cone 7 and balls 17 serves to distribute the air in theraceway and around the balls and; ultimately and through passage 18between the spindle 5 and cone 7. That portion of the air, indicated at40, that passes through jet holes 4: acts to clean the teeth of cone 7and to flush out cuttings from the hole being drilled as is well knownin the art.

Referring now to Fig. 2 an. embodiment of this invention is shown whichis particularly adapted to low pressure high velocity air course drillbits. Numeral 2A represents the shank which includes a large centralopening 4A and angularly drilled channel 10- as before. The balance ofthis drill bit corresponds to that shown in Fig. 1 with the exception ofinsert 41 which. comprises a long tube having an angularly disposedupper end 42 which extends a distance into the air stream in chamber 3A.Insert 41 may extend any desired distance into cavity 3A up to thecenter thereof. The exposed end 42 is essential when using this drillbit with low pressure air, since the high velocity airstream indicatedby arrow 43 would pass right by the opening of channel 10 as seen inFig. 1. However with a large opening 45 exposed directly in theairstream, an increased quantity of air will be delivered through insert41 and channels 11 and 12 to raceway 15, where the rotating balls 17will carry the air around the raceway and eventually out passage 18. Itshould be observed that insert 41 may be constructed of copper tubingand be utilized in indentically the same installation as shown in Fig.5.

An additional means of securing the insert in place may be seen byreference to Fig. 6. In this embodiment, the insert is a short straightpiece of tubing which is inserted, at its ends in counterbore 51 inshank 2C and counterbore 52 in spindle 5C. The air channels 53 and5;4entering the respective counterbores are of a reduced diameter so as toprovide shoulders 55 and 56 at the intersection of each channel andcounterbore. Insert 50 is slightly shorter than the distance between theshoulders to allow for machining tolerances.

Figs. 3 and 4 illustrate the indentures 60 to permit air and cuttings toprocede up and out of the drilled hole, and Fig. 4 shows tines 61 whichsupport spindle 5 at assembly. The section line 1-1 of Fig. 4 indicatesthe section of shank 2 which is shown in Fig. 1. Spindle 5 is showninserted between tines 61 so that its air channel 11 aligns with airchannel of shank 2. Welding 6 then per manently attaches portion 105 ofspindle 5 in the space adjacent the flats or lands indicated as 27between tines 61.

It has been found beneficial in employing air as we have to cool thehearings to inject a fine spray of oil into the air stream to lubricatethe bearings 17. This is accomplished by means of either a pressureoperated or Venturi operated line mist oiler. When employing this methodof lubrication it is desirable to form, the insert as shown in Fig. 7.The insert identified as 42A includes a long acutely tapered opening 45Awhich provides a much greater opening to gather an increased number ofoil molecules represented by 64 in airstream 43A. Additionally certainof the molecules 65 collecton the inner wall 67 of shank 2A and drop bygravity down the wall to point 66, below which they drop into theinterior of tube 42A and recombine with the airstream 46A to thebearings 17. Insert 42A is shown in Fig. 7 to be perpendicularlytransverse to the airstream 43A and this position affords a maximumopening to the air from the top. In some instances it is desirable torotate the insert 42A so that the large opening 45B is facing thedirection of rotation of the drill bit whereby it provides a scoop toforce air and lubricant into the opening and to raceway 15. It will beobserved that some of the air entering raceway from channel 12 underpressure will pass between adjacent balls 17 and carry lubricant on upinto passageway 69 (Fig. 2).

From the foregoing description it will be readily seen that there hasbeen produced a device which substantially fulfills the objects of theinvention as set forth herein.

While this specification sets forth in detail the present and preferredconstruction of this invention, still in practice such deviations fromsuch detail may be resorted to as do not form a departure from thespirit of the invention as defined in the appended claims.

Having thus described the invention, what is claimed as new and usefuland is desired to be secured by Letters Patent is:

1. A drill bit comprising a shank having an air chamber therein, saidchamber being open and registerable with a drill string for flow of airinto said air chamber, said chamber including an opening in its lowerend to permit passage of air therethrough, downwardly projecting tinesat the lower end of said shank, said tines being spaced in pairs aboutthe circumference of said shank, a

land between each pair of tines, a spindle inserted between each pair oftines and attached thereto but being spaced from said land, a cuttercone mounted on each 'spindle and adapted to rotate thereabout, bearingmeans between said cone and spindle, a channel in said shank leadingfrom said chamber to said land, a channel in each spindle leading tosaid bearing means, said channels in said shank and spindle being inalignment, and connecting means between said aligned channels, saidchannels and insert providing a continuous path from said air chamber tosaid bearing means.

2. Adrill bit comprising a shank having an air chamber therein, saidchamber being open and registerable with a drill string for flow of airinto said air chamber, said chamber including an opening in its lowerend to permit passage of air therethrough, downwardly projecting tinesat the lower end of said shank, said tines being spaced in pairs aboutthe circumference of said shank, a land between each pair of tines, aspindle inserted between each pair of tines and attached thereto butbeing spaced from said land, a cutter cone mounted on each spindle andadapted to rotate thereabout, bearing means between said cone andspindle, a channel in said shank leading from said chamber to said land,a channel in each spindle leading to said bearing means, said channelsin said shank and spindle being in alignment, and a tubular insertextending into and between said aligned channels, said channels andisert providing a continuous path from said air chamber to said bearingmeans, a shoulder on said insert between said land and the adjacent sideof the spindle for preventing longitudinal movement of said insert insaid channels.

3. A drill bit comprising a shank having an air chamber therein, saidchamber being open and registerable with i a drill string for flow ofair into said air chamber, said chamber including an opening in itslower end to permit passage of air therethrough, spindles attached tosaid shank, a cutter cone mounted on each spindle and rotatingthereabout, bearing means between said cone and said spindle, a channelin said shank leading from said chamber to one surface of said shank, achannel in said spindle leading from a surface of said spindle to saidbearing means, said channels in said shank and spindle being inalignment, and a tubular insert extending into said air chamber, throughsaid shank channel and into said spindle channel in close fittingrelation with said channels, said channels and insert providing acontinuous air path from said air chamber to said bearing means.

4. A drill bit comprising a shank having an air'chamber therein, saidchamber being open and registerable with a drill string for fioW of airinto said air chamber, said chamber including an opening in its lowerend to permit passage of air therethrough, spindles attached to saidshank, a cutter cone mounted on each spindle and rotatable thereabout,bearing means between said cone and said spindle, a channel in saidshank leading from said chamber to one surface of said shank, a channelin said spindle leading from a surface of said spindle to said bearingmeans, said channels in said shank and spindle being in alignment, and atubular insert extending into said air chamber, through said shankchannel and into said spindle channel in close fitting relation withsaid channels said channels and insert providing a continuous air pathfrom said air chamber to said bearing means, the end of said insertexposed to said air chamber being cut on a bias and facing upward toprovide a greater exposed opening to air entering said air chamber.

5. A drill bit comprising a shank having an air chamber therein, saidchamber being open and registerable with a drill string for flow of airinto said air chamber, said chamber including an opening in its lowerend to permit passage of air therethrough, spindles attached to saidshank, a cutter cone mounted on each spindle and rotatable thereabout,bearing means between said cone and said spindle, a channel in saidshank leading from said chamber to one surface of said shank, a channelin said spindle leading from a surface of said spindle to said bearingmeans, said channels in said shank and spindle being in alignment, and atubular insert extending into said air chamber, through said shankchannel and into said spindle channel in close fitting relation withsaid channels said channels and insert providing a continuous air pathfrom said air chamber to said bearing means, said aligned channelshaving the same inside diameter. and said tubular insert having anoutside diameter slightly smaller than said channel diameter at a crosssection therethrough adjacent its ends and having an outside diameterlarger than said channel diameter at a cross section therethroughbetween said shank and spindle.

6. A drill bit comprising a shank having an air chamber therein, saidchamber being open and registcrable with a drill string for fiow of airinto said air chamber, said chamber having an opening in its lower endto permit passage of air therethrough, spindles attached to said shank,a cutter cone mounted on each spindle rotatable thereabout, bearingmeans between said cone and said spindle, a channel in said shankleading from said chamber to one surface of said shank, a channel insaid spindle leading from a surface of said spindle to said bearingmeans, said channels in said shank and spindle being in alignment, saidspindle channel being counterbored with a smaller diameter than saidshank channel, a tubular insert including a crimped end, said crirnpedend being pressed into said counterbore, the other end of said insertextending into said shank channel, said channels and insert providing acontinuous passage for air from said air chamber to said bearing means.

7. A drill bit comprising a shank having an air chamber therein, saidchamber being open and registerable with a drill string for flow of airinto said air chamber, said chamber having an opening in its lower endto permit passage of air therethrough, spindles attached to said shank,a cutter cone mounted on each spindle rotatable thereabout, bearingmeans between said cone and said spindle, a channel in said shankleading from said chamber to one surface of said shank, a channel insaid spindle leading from a surface of said spindle to said bearingmeans, said channels in said shank and spindle being in alignment, bothsaid channels being counterbored, and a relatively short lengthcontinuous diameter tubular insert extending into and between saidcounterbores said channels and insert providing a continuous air pathfrom said air chamber to said bearing means.

8. A drill bit comprising a shank having an air chamber therein, saidchamber being open and registerable with a drill string for flow of airinto said air chamber, said chamber having an opening in its lower endto permit passage of air therethrough, spindles attached to said shank,a cutter cone mounted on each spindle and rotatable thereabout, bearingmeans between said cone and said spindle, a channel in said shankleading from said chamber to one surface of said shank, a channel insaid spindle leading from a surface of said spindle to said bearingmeans, said channels in said shank and spindle being in alignment, and atubular insert extending into and between said aligned channels, saidchannels and insert providing a continuous air path from said airchamber to said bearing means, said insert extending into said airchamber and terminating therein, said terminant end of that portion ofsaid insert extending into said chamber being open in a verticaldirection.

9. A drill bit comprising a shank having an air chamber therein, saidchamber being open and registerable with a drill string for flow of airinto said air chamber, said chamber having an opening in its lower endto permit passage of air therethrough, spindles attached to said shank,a cutter cone mounted on each spindle and rotatable thereabout, bearingmeans between said cone and said spindle, a channel in said shankleading from said chamber to one surface of said shank, a channel insaid spindle leading from a surface of said spindle to said bearingmeans, said channels in said shank and spindle being in alignment, and atubular insert extending into and between said aligned channels, saidchannels and insert providing a continuous air path from said airchamber to said bearing means, said insert extending into said airchamber and terminating therein, said terminant end of that portion ofsaid insert extending into said chamber being open in the direction ofrotation of said drill bit.

10. A drill bit comprising a shank having an air chamber therein, saidchamber being open and registerable with a drill string for flow of airinto said air chamber, said chamber having an opening in its lower endto permit passage of air therethrough, spindles attached to said shank,a cutter cone mounted on each spindle rotatable thereabout, bearingmeans between said cone and said spindle, a channel in said shankleading from said cl1amher to one surface of said shank, a channel insaid spindle leading from a surface of said spindle to said bearingmeans, said channels in said shank and spindle being in alignment, andconnecting means between said aligned channels, said channels and insertproviding a continuous air path from said air chamber to said bearingmeans, said connecting means extending into said air chamber andterminating therein, said terminant end being open and comprising ascoop to force air into said continuous air path.

11. A drill bit comprising a shank having a fluid chamber therein, saidchamber including an opening in its lower end to permit passage of fluidtherethrough from the chamber, downwardly projecting tines at the lowerend of said shank, said tines being arranged in at least one pair andspaced about the circumference of said shank, a land between the pair oftines, a spindle inserted between the pair of tines and attached theretobut being spaced from said land, a cutter mounted on the spindle andadapted to rotate thereabout, bearing means between said cutter andspindle, said shank having a channel therein leading from the opening inthe lower end of said chamber to said land, the spindle having a channeltherein leading to said bearing means, said channels in the shank andspindle being in alignment, and connecting means between said alignedchannels, said channels and connecting means providing a continuous pathfrom said chamber to said hearing means.

References Cited in the file of this patent UNITED STATES PATENTS1,254,267 Pickin Jan. 22, 1918 1,302,967 Pickin May 16, 1919 1,306,371Culmore June 10, 1919 1,334,632 Pickin Mar. 23, 1920 1,537,551 Reed May12, 1925 1,784,476 Zublin et a1. Dec. 9, 1930 1,816,203 Behnke July 28,1931 1,83 8,045 Wadsworth Nov. 22, 1931 1,902,941 Bailey Mar. 28, 19331,945,240 Tupica Jan. 30, 1934 2,063,012 Catland Dec. 8, 1936 2,087,500Catland July 30, 1937 2,122,758 Scott July 5, 1938 2,329,745 Crook Sept.21, 1943 2,661,932 Woods Dec. 8, 1953

